This research seeks to develop techniques for efficient long-term reproduction of the owl monkey, Aotus trivirgatus. The major goal is to achieve a self-sustaining colony, one which replaces itself as well as produces surplus animals for research. Owl monkeys are priority animal models for research in malaria and viral oncology. The national need is not being met by importation or current breeding programs. We reason that Aotus will reproduce efficiently in captivity over successive generations if management principles are founded in the unique biological characteristics of the genus. Management must be responsive, we believe, to the need for karyotypic hemogeneity of breeding pairs to various avenues of reducing stress in captivity, and to the very active nature of these animals. In addition we will determine to what extent it is essential for young animals to remain with their parents to learn complex sexual and parental behaviors. The effectiveness of these management techniques will be measured through ethological and physiological observations. Pregnancy will be monitored by recognizing chorionic gonadotropin in the urine using the non-human primate pregnancy test. Cycling of other reproductive hormones will be monitored with thin layer chromatography. The behavior of pairs that successfully breed and rear young will be compared with those pairs that fail to breed or to care well for infants. These observations will be carefully correlated with information on physiological state. On the basis of our monitoring, a stock of Aotus will be selected which is adapted to captive breeding and successful rearing of infants. In this way we intend to establish methods of husbandry and breeding through which the national needs for Aotus supply can be met.